Human and animal vaccines have been commercially produced by growing the desired virus in primary cells which must be grown on surfaces. Commercial processes were initially developed in Brockway bottles and, as production techniques evolved, the Brockway bottles were replaced by roller bottles. More recently, mass culture systems have been developed, including those which utilize a series of concentric rings or tanks having a plurality of stacked plates. The most recent mass culture system which has been developed is the multiplate machine produced by Biotec A. B. of Sweden which contains a series of titanium discs or plates which are mounted on a rotatable shaft in a cylindrical glass vessel. The vessel is capable of being placed in the upright position, in which the plating surface of the discs is in a horizontal plane in order to permit the cells to settle onto the plating surface of the discs. The device is then placed on its side so that the plated cells are rotated through the growth medium in the vessel until cell sheet formation occurs, the virus seed is then added, the unit is again rotated and the vaccine is harvested. In prior systems of cell cultivation, scale-up to large units has sometimes been difficult as flow patterns at the desired low velocities are not uniform and variations in growth conditions exist.